• The Plant Pathology Journal
• /
• 제36권1호
• /
• pp.43-53
• /
• 2020

Ralstonia solanacearum (Rso) is a causal agent of bacterial wilt in Solanaceae crops worldwide including Republic of Korea. Rso virulence predominantly relies on type III secreted effectors (T3Es). However, only a handful of Rso T3Es have been characterized. In this study, we investigated subcellular localization of and manipulation of plant immunity by 8 Rso T3Es predicted to harbor a nuclear localization signal (NLS). While 2 of these T3Es elicited cell death in both Nicotiana benthamiana and N. tabacum, only one was dependent on suppressor of G2 allele of skp1 (SGT1), a molecular chaperone of nucleotide-binding and leucine-rich repeat immune receptors. We also identified T3Es that differentially regulate flg22-induced reactive oxygen species production and gene expression. Interestingly, several of the NLS-containing T3Es translationally fused with yellow fluorescent protein accumulated in subcellular compartments other than the cell nucleus. Our findings bring new clues to decipher Rso T3E function in planta.

• Molecules and Cells
• /
• 제25권3호
• /
• pp.368-375
• /
• 2008

Approximately 120 UDP-glycosyltransferases (UGTs), which are classified into 14 distinct groups (A to N), have been annotated in the Arabidopsis genome. UGTs catalyze the transfer of sugars to various acceptor molecules including flavonoids. Previously, UGT71C1 was shown to glycosylate the 3-OH of hydroxycinnamates and flavonoids in vitro. Such secondary metabolites are known to play important roles in plant growth and development. To help define the role of UGT71C1 in planta, we investigated its expression patterns, and isolated and characterized a loss-of-function mutation in the UGT71C1 gene (named ugt71c1-1). Our analyses by quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR), microarray data mining, and histochemical detection of GUS activity driven by the UGT71C1 promoter region, revealed the tissue-specific expression patterns of UGT71C1 with highest expression in roots. Interestingly, upon treatment with methyl viologen (MV, paraquat), ugt71c1-1 plants displayed enhanced resistance to oxidative stress, and ROS scavenging activity was higher than normal. Metabolite profiling revealed that the levels of two major glycosides of quercetin and kaempferol were reduced in ugt71c1-1 plants. In addition, when exposed to MV-induced oxidative stress, eight representative ROS response genes were expressed at lower levels in ugt71c1-1 plants, indicating that ugt71c1-1 probably has higher non-enzymatic antioxidant activity. Taken together, our results indicate that ugt71c1-1 has increased resistance to oxidative stress, suggesting that UGT71C1 plays a role in some glycosylation pathways affecting secondary metabolites such as flavonoids in response to oxidative stress.

• Journal of Ginseng Research
• /
• 제41권3호
• /
• pp.403-410
• /
• 2017

Background: Prenyltransferases catalyze the sequential addition of isopentenyl diphosphate units to allylic prenyl diphosphate acceptors and are classified as either trans-prenyltransferases (TPTs) or cis-prenyltransferases (CPTs). The functions of CPTs have been well characterized in bacteria, yeast, and mammals compared to plants. The characterization of CPTs also has been less studied than TPTs. In the present study, molecular cloning and functional characterization of a CPT from a medicinal plant, Panax ginseng Mayer were addressed. Methods: Gene expression patterns of PgCPT1 were analyzed by quantitative reverse transcription polymerase chain reaction. In planta transformation was generated by floral dipping using Agrobacterium tumefaciens. Yeast transformation was performed by lithium acetate and heat-shock for $rer2{\Delta}$ complementation and yeast-two-hybrid assay. Results: The ginseng genome contains at least one family of three putative CPT genes. PgCPT1 is expressed in all organs, but more predominantly in the leaves. Overexpression of PgCPT1 did not show any plant growth defect, and its protein can complement yeast mutant $rer2{\Delta}$ via possible protein-protein interaction with PgCPTL2. Conclusion: Partial complementation of the yeast dolichol biosynthesis mutant $rer2{\Delta}$ suggested that PgCPT1 is involved in dolichol biosynthesis. Direct protein interaction between PgCPT1 and a human Nogo-B receptor homolog suggests that PgCPT1 requires an accessory component for proper function.

• Journal of Microbiology and Biotechnology
• /
• 제26권6호
• /
• pp.1103-1108
• /
• 2016

Yam anthracnose caused by Colletotrichum gloeosporioides (C.g) is the most devastating disease of yam (Dioscorea sp.). In the present study, we evaluated the culture filtrate extract (CFE) of azalomycin-producing Streptomyces malaysiensis strain MJM1968 for the control of yam anthracnose. MJM1968 showed strong antagonistic activity against C.g in vitro. Furthermore, the MJM1968 CFE was tested for inhibition of spore germination in C.g, where it completely inhibited spore germination at a concentration of 50 μg/ml. To assess the in planta efficacy of the CFE and spores of MJM1968 against C.g, a detached leaf bioassay was conducted, which showed both the treatments suppressed anthracnose development on detached yam leaves. Furthermore, a greenhouse study was conducted to evaluate the CFE from MJM1968 as a fungicide for the control of yam anthracnose. The CFE non-treated plants showed a disease severity of >92% after 90 days of artificial inoculation with C.g, whereas the disease severity of CFE-treated and benomyl-treated yam plants was reduced to 26% and 15%, respectively, after 90 days. Analysis of the yam tubers from the CFE-treated and non-treated groups showed that tubers from the CFE-treated plants were larger than that of non-treated plants, which produced abnormal smaller tubers typical of anthracnose. This study demonstrated the utility of the CFE from S. malaysiensis strain MJM1968 as a biofungicide for the control of yam anthracnose.

• The Plant Pathology Journal
• /
• 제32권5호
• /
• pp.469-480
• /
• 2016

Bacterial wilt and grey mould in tomato plants are economically destructive bacterial and fungal diseases caused by Ralstonia solanacearum and Botrytis cinerea, respectively. Various approaches including chemical and biological controls have been attempted to arrest the tomato diseases so far. In this study, in vitro growths of bacterial R. solanacearum and fungal B. cinerea were evaluated using four different vitamins including thiamine (vitamin B1), niacin (vitamin B3), pyridoxine (vitamin B6), and menadione (vitamin K3). In planta efficacies of the four vitamin treatments on tomato protection against both diseases were also demonstrated. All four vitamins showed different in vitro antibacterial activities against R. solanacearum in dose-dependent manners. However, treatment with 2 mM thiamine was only effective in reducing bacterial wilt of detached tomato leaves without phytotoxicity under lower disease pressure ($10^6$ colony-forming unit [cfu]/ml). Treatment with the vitamins also differentially reduced in vitro conidial germination and mycelial growth of B. cinerea . The four vitamins slightly reduced the conidial germination, and thiamine, pyridoxine and menadione inhibited the mycelial growth of B. cinerea. Menadione began to drastically suppress the conidial germination and mycelial growth by 5 and 0.5 mM, respectively. Grey mould symptoms on the inoculated tomato leaves were significantly reduced by pyridoxine and menadione pretreatments one day prior to the fungal challenge inoculation. These findings suggest that disease-specific vitamin treatment will be integrated for eco-friendly management of tomato bacterial wilt and grey mould.

• Journal of Microbiology and Biotechnology
• /
• 제32권2호
• /
• pp.160-169
• /
• 2022

In the present study we evaluated the efficacy of a bioformulation of Streptomyces cameroonensis for control of black pod disease in cocoa and enhancement of seedling growth. The formulation developed using talc powder and cassava starch as carriers showed high shelf-life of 1.07 × 10⁶ CFU/g after six months storage at 4℃. The formulation was tested for inhibition of spore germination in Phytophthora megakarya and showed 100% inhibition at 10% (w/v) of formulation. To determine the efficacy of the formulation, we performed an in planta assay in the greenhouse on two hybrids of cocoa seedlings, the tolerant SNK413 × (♂) T79/467 and the susceptible UPA 134× (♂) SCA 12. Detached leaf assay showed a significant reduction in the disease severity index of about 67% for the tolerant hybrid and 55% for the susceptible hybrid compared to non-treated plants. A significant enhancement in stem length, leaf surface area and root weight was observed. Analysis of biochemical markers of defense showed a significant increase in total polyphenol, flavonoid, and total protein contents. There was also significant upregulation of PR-proteins such as chitinases, peroxidases and β-1, 3-glucanases following treatment of both tolerant and susceptible hybrids, though with a higher level of synthesis in the tolerant hybrids. A significant increase was also observed in polyphenol oxidase activities in plants treated with the formulation. This work demonstrated the stability and effectiveness of the S. cameroonensis powder formulation in suppressing black pod disease in cocoa and subsequently enhancing the growth of seedlings.

• The Plant Pathology Journal
• /
• 제40권5호
• /
• pp.438-450
• /
• 2024

Arabidopsis MORC1 (Microrchidia) is required for multiple levels of immunity. We identified 14 MORC1-interacting proteins (MIPs) via yeast two-hybrid screening, eight of which have confirmed or putative nuclear-associated functions. While a few MIP mutants displayed altered bacterial resistance, MIP13 was unusual. The MIP13 mutant was susceptible to Pseudomonas syringae, but when combined with morc1/2, it regained wild-type resistance; notably, morc1/2 is susceptible to the same pathogen. MIP13 encodes MED9, a mediator complex component that interfaces with RNA polymerase II and transcription factors. Expression analysis of defense genes PR1, PR2, and PR5 in response to avirulent P. syringae revealed that morc1/2 med9 expressed these genes in a slow but sustained manner, unlike its lower-order mutants. This expression pattern may explain the restored resistance and suggests that the interplay of MORC1/2 and MED9 might be important in curbing defense responses to maintain fitness. Indeed, repeated challenges with avirulent P. syringae triggered significant growth inhibition in morc1/2 med9, indicating that MED9 and MORC1 may play an important role in balancing defense and growth. Furthermore, the in planta interaction of MED9 and MORC1 occurred 24 h, not 6 h, post-infection, suggesting that the interaction functions late in the defense signaling. Our study reveals a complex interplay between MORC1 and MED9 in maintaining an optimal balance between defense and growth in Arabidopsis.

• 식물병연구
• /
• 제15권2호
• /
• pp.120-126
• /
• 2009

Botrytis cinerea 균주의 병원성에 있어서 phytotoxin의 역할을 규명하는 연구를 하던 중에 B. cinerea 2-16균주가 생산하는 새로운 phytotoxin을 분리 동정하였다. 두 개의 물질은 3-O-acetyl botcinol과 3-O-acetyl botcinolide로 동정되었다. 본 연구는 두 개의 물질과 B. cinerea의 병원성과의 상관관계를 규명하고자 실시하였다. 25개의 B. cinerea 균주 중에서 병원성이 약한 3개의 B. cinerea 균주는 액체배지에서 두 phytotoxin을 생산하지 않았다. 병원성이 강하거나 중간정도인 균주들은 두 phytotoxin을 생산하는 균과 생산하지 않는 균으로 나뉘었다. 한편, 25개의 균주 중에서 10균주의 액체배양액 에틸아세테이트 추출물이 9개의 식물체를 이용한 whole plant assay에서 phytotoxicity를 나타냈으며, 이들 10개 추출물 모두에서 두 phytotoxin이 검출되었다. In planta 실험에서는 병원성이 강한 균주에 감염된 식물조직에서 모두 두 phytotoxin이 검출되었다. 하지만 두 phtotoxin의 생산량과 병원성과는 상관관계를 보이지 않았다. 두 phytotoxin은 B. cinerea 2-16 균주에 감염된 토마토 조직에서 3일째부터 검출되기 시작해 4일째는 가장 크게 증가하였으며 그 후 감소하였다. 이상의 실험 결과 3-O-acetyl botcinol과 3-O-acetyl botcinolide는 B. ciuereo의 발병과정에 있어서 중요한 역할을 할 것으로 추정되지만 병을 일으키는데 일차적인 요인은 아닐 것으로 사료된다.

• The Plant Pathology Journal
• /
• 제33권5호
• /
• pp.499-507
• /
• 2017

In an attempt to develop a biological control agent against mycotoxigenic Fusarium species, we isolated Bacillus amyloliquefaciens strain DA12 from soil and explored its antimicrobial activities. DA12 was active against the growth of mycotoxigenic F. asiaticum, F. graminearum, F. proliferatum, and F. verticillioides both in vitro and in planta (maize). Further screening using dual culture extended the activity range of strain DA12 against other fungal pathogens including Botrytis cinerea, Colletotrichum coccodes, Endothia parasitica, Fusarium oxysporum, Raffaelea quercus-mongolicae, and Rhizoctonia solani. The butanol extract of the culture filtrate of B. amyloliquefaciens DA12 highly inhibited the germination of F. graminearum macroconidia with inhibition rate 83% at a concentration of $31.3{\mu}g/ml$ and 100% at a concentration of $250{\mu}g/ml$. The antifungal metabolite from the butanol extract was identified as iturin A by thin layer chromatography-bioautography. In addition, volatile organic compounds produced by DA12 were able to inhibit mycelial growth of various phytopathogenic fungi. The volatile compounds were identified as 2-heptanone, 5-methyl heptanone and 6-methyl heptanone by gas chromatography-mass spectrometry (GC-MS) analysis. These results indicate that the antagonistic activity of Bacillus amyloliquefaciens DA12 was attributable to iturin A and volatile heptanones, and the strain could be used as a biocontrol agent to reduce the development of Fusarium diseases and mycotoxin contamination of crops.

• Journal of Acupuncture Research
• /
• 제18권1호
• /
• pp.217-225
• /
• 2001

Objectives and Mtthods : In order to study on the Effect of Strychni Semen aqua-acupuncture on the arthritis induced by injecting Freund's complete adjuvant to the right posterior planta of rat's foot, rats were divided 5 groups equally, one group was not treated(Normal) and the other groups were induced arthritis by injecting Freund's complete adjuvant(Control, ST, SS, SST). Control was not treated after injecting of Freund's complete adjuvant. ST was 0.2cc Saline-injected Group at Chok-Samni(ST36) either days during 2 weeks after injecting of Freund's complete adjuvant. SS was 0.2cc Strychni Semen-subcutaneous injected group either days during 2 weeks after injecting of Freund's complete adjuvant. SST was 0.2cc Strychni Semen-injected group at Chok-Samni(ST36) either days during 2 week after injecting of Freund's complete adjuvant. And then effect of Strychni Semen aqua-acupuncture on the edema, numbers of blood WBC, platelet, hematocrit, contented quantities of total protein, albumin in rats with F.C.A were measured. Results : The following results have been obtained. 1. In effect of Strychni Semen aqua-acupuncture on plantar edema, SS showed significant decrease compared with control. 2. In effect of Strychni Semen aqua-acupuncture on WBC, SS and SST showed significant decrease compated with control. 3. In effect of Strychni Semen aqua-acupuncture on platelet, SS and SST did not show significant decrease. 4. In effect of Strychni Semen aqua-acupuncture on hematocrit, SST showed significant increase compared with control. 5. In effect of Strychni Semen aqus-acupuncture on the contents quantity of total protein and albumin, SS showed significant increase compared with control: Conclusions : Accoring to this result, Strychni Semen aqua-acupunture inserted into Chok-Samn i(ST36) appeared to have effect on Adjuvant arthritis of rats. Therefore it is oxpected that Strychni Semen aqua-acupunture may be available clinically.